mirror of https://github.com/hpcaitech/ColossalAI
126 lines
6.4 KiB
Python
126 lines
6.4 KiB
Python
from typing import Optional
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import torch
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import torch.distributed as dist
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import torch.nn as nn
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import torch.optim as optim
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import colossalai
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from colossalai.nn.optimizer import CPUAdam, HybridAdam
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from colossalai.nn.parallel import zero_model_wrapper, zero_optim_wrapper
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from colossalai.tensor import ProcessGroup, ShardSpec
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from colossalai.utils import get_current_device
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from colossalai.utils.model.colo_init_context import ColoInitContext
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from .ddp import DDPStrategy
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class ColossalAIStrategy(DDPStrategy):
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"""
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The strategy for training with ColossalAI.
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Args:
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stage(int): The stage to use in ZeRO. Choose in (1, 2, 3)
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seed(int): The seed for the random number generator.
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shard_init(bool): Whether to shard the model parameters during initialization. Only for ZeRO-3.
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placement_policy(str): The placement policy for gemini. Choose in ('cpu', 'cuda')
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If it is “cpu”, parameters, gradients and optimizer states will be offloaded to CPU,
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If it is “cuda”, they will not be offloaded, which means max CUDA memory will be used. It is the fastest.
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pin_memory(bool): Whether to pin the memory for the data loader. Only for ZeRO-3.
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force_outputs_fp32(bool): Whether to force the outputs to be fp32. Only for ZeRO-3.
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search_range_mb(int): The search range in MB for the chunk size. Only for ZeRO-3.
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hidden_dim(optional, int): The hidden dimension for the gemini. Only for ZeRO-3.
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min_chunk_size_mb(float): The minimum chunk size in MB. Only for ZeRO-3.
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gpu_margin_mem_ratio(float): The margin memory ratio for the GPU. Only for ZeRO-3.
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reduce_bugket_size(int): The reduce bucket size in bytes. Only for ZeRO-1 and ZeRO-2.
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overlap_communication(bool): Whether to overlap communication and computation. Only for ZeRO-1 and ZeRO-2.
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initial_scale(float): The initial scale for the optimizer.
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growth_factor(float): The growth factor for the optimizer.
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backoff_factor(float): The backoff factor for the optimizer.
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growth_interval(int): The growth interval for the optimizer.
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hysteresis(int): The hysteresis for the optimizer.
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min_scale(float): The minimum scale for the optimizer.
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max_scale(float): The maximum scale for the optimizer.
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max_norm(float): The maximum norm for the optimizer.
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norm_type(float): The norm type for the optimizer.
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"""
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def __init__(
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self,
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stage: int = 3,
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seed: int = 42,
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shard_init: bool = True, # only for stage 3
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placement_policy: str = 'cuda',
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pin_memory: bool = True, # only for stage 3
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force_outputs_fp32: bool = False, # only for stage 3
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search_range_mb: int = 32, # only for stage 3
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hidden_dim: Optional[int] = None, # only for stage 3
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min_chunk_size_mb: float = 32, # only for stage 3
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gpu_margin_mem_ratio: float = 0.0, # only for stage 3
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reduce_bucket_size: int = 12 * 1024**2, # only for stage 1&2
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overlap_communication: bool = True, # only for stage 1&2
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initial_scale: float = 2**16,
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growth_factor: float = 2,
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backoff_factor: float = 0.5,
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growth_interval: int = 1000,
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hysteresis: int = 2,
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min_scale: float = 1,
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max_scale: float = 2**32,
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max_norm: float = 0.0,
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norm_type: float = 2.0) -> None:
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super().__init__(seed)
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assert placement_policy in ('cpu', 'cuda'), f'Unsupported placement policy "{placement_policy}"'
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self.stage = stage
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self.shard_init = shard_init
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self.gemini_config = dict(device=get_current_device(),
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placement_policy=placement_policy,
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pin_memory=pin_memory,
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force_outputs_fp32=force_outputs_fp32,
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strict_ddp_mode=shard_init,
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search_range_mb=search_range_mb,
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hidden_dim=hidden_dim,
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min_chunk_size_mb=min_chunk_size_mb)
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if stage == 3:
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self.zero_optim_config = dict(gpu_margin_mem_ratio=gpu_margin_mem_ratio)
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else:
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self.zero_optim_config = dict(reduce_bucket_size=reduce_bucket_size,
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overlap_communication=overlap_communication,
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cpu_offload=(placement_policy == 'cpu'))
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self.optim_kwargs = dict(initial_scale=initial_scale,
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growth_factor=growth_factor,
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backoff_factor=backoff_factor,
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growth_interval=growth_interval,
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hysteresis=hysteresis,
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min_scale=min_scale,
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max_scale=max_scale,
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max_norm=max_norm,
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norm_type=norm_type)
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def setup_distributed(self) -> None:
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colossalai.launch_from_torch({}, seed=self.seed)
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def model_init_context(self):
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if self.stage == 3:
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world_size = dist.get_world_size()
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shard_pg = ProcessGroup(tp_degree=world_size) if self.shard_init else None
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default_dist_spec = ShardSpec([-1], [world_size]) if self.shard_init else None
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return ColoInitContext(device=get_current_device(),
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dtype=torch.half,
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default_pg=shard_pg,
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default_dist_spec=default_dist_spec)
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return super().model_init_context()
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def setup_model(self, model: nn.Module) -> nn.Module:
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return zero_model_wrapper(model, zero_stage=self.stage, gemini_config=self.gemini_config)
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def setup_optimizer(self, optimizer: optim.Optimizer, model: nn.Module) -> optim.Optimizer:
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assert isinstance(optimizer, (CPUAdam, HybridAdam)), f'Unsupported optimizer {type(optimizer)}'
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return zero_optim_wrapper(model, optimizer, optim_config=self.zero_optim_config, **self.optim_kwargs)
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def backward(self, loss: torch.Tensor, model: nn.Module, optimizer: optim.Optimizer, **kwargs) -> None:
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optimizer.backward(loss)
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def optimizer_step(self, optimizer: optim.Optimizer, **kwargs) -> None:
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optimizer.step()
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